Hi,
I'm a new player, and I suppose somebody may have hinted that fact, but the gas mask must be put on anew after replenishing ammo and all from the stash. Seems weird. Just wanted to point that out, thanks.

Yah, it is kinda weird. Since it also fully heals you, and this is a "realistic" shooter, I like to think of it more like you're just a totally new dude walking in to full the shoes of the guy you were just controlling. He may even have totally different gear too.